diff --git a/ant_landscape/ant_functions.py b/ant_landscape/ant_functions.py
index b4e1e1f58c10095e0acee3415dbdce7481fd7b6c..3c3c2c713b40f04c8322c6b321fa11599c1a3e93 100644
--- a/ant_landscape/ant_functions.py
+++ b/ant_landscape/ant_functions.py
@@ -137,7 +137,7 @@ class AntLandscapeRefresh(bpy.types.Operator):
     @classmethod
     def poll(cls, context):
         ob = bpy.context.active_object
-        return (ob.ant_landscape and not ob.ant_landscape['sphere_mesh'])
+        return (ob.ant_landscape and not ob.ant_landscape.sphere_mesh)
 
 
     def execute(self, context):